FRIDAY, June 29 (HealthDay News) -- Heterosexual couples often have trouble with sex and intimacy issues after they become parents, and a new study suggests that gay parents face some of the same challenges.

"When gay couples become parents, they become very focused on the kids, they are tired, there is less time for communication and less desire for sex," Colleen Hoff, a professor of sexuality studies at San Francisco State University, said in a university news release. "They go through a lot of the same changes as heterosexual couples who have kids."

An estimated one in five gay male couples nationwide is raising children. For the new study, 48 gay male couples who are raising children together were interviewed and asked questions about their lives.

"We found that gay fathers have less time for sex and less emphasis on sexuality, which could mean they are at less risk for HIV," Hoff said. "Many fathers said they feel a sense of responsibility toward their children which motivates them to avoid risky sexual behavior."

Not many of the men were concerned about the changes in their sex lives, according to the report published in the June issue of the journal Couple and Family Psychology.

"From the fathers we studied, there was this pragmatic acceptance that this is what happens at this stage of life," Hoff pointed out.

Hoff and colleagues also found that the men tended to follow the same rules about sexual activity outside their partnership after becoming parents as they did before.

"There wasn't the shift that we thought we might find," Hoff said. "For the most part, those who were monogamous before becoming parents said they stayed with that arrangement. Those who had open relationships before having children reported that they kept to that agreement."

The findings suggest that gay male parents who are in open relationships might be less willing to talk to others, such as physicians, about the choices they've made.

"Some men felt that there is this assumption that if you are a gay parent you are monogamous," Hoff explained. "This kind of stigma around gay parents' sexuality could be a concern if gay fathers are reluctant to talk to their physician about their sexual agreement and get tested for HIV."